Street-network Sprawl in Calama, Chile

What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

To see the state of street-network sprawl across the globe, visit the sprawlmap.

Calama: city in Antofagasta, Chile

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Calama, Chile on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Calama as of 2014, the overall level of street-network sprawl is 1.03, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.13, 0.86, 0.79 and 0.92. The disconnectivity of new streets constructed in Calama fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Calama spans a total of 414 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.13, which is relatively well-connected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 1.13, 1.08, 1.05 and 1.03. Overall, the SNDi of the aggregate street network has fallen: the street network in Calama has become more connected.

Calama and Antofagasta do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Calama was at its lowest in 1991-2000, while the SNDi of street constructions in Antofagasta peaked in 1976-1990.

How do development practices in Calama fare in comparison to others in Antofagasta? Most recently in 2001-2014, street construction in Calama was the 1st-most disconnected out of the 2 cities in Antofagasta. Its position in the ranks since 1975 has not changed. Calama ranked 1st in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 1st in 2001-2014.

Calama and Chile do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Calama was at its lowest in 1991-2000, while the SNDi of street constructions in Chile rose steadily.

How do development practices in Calama fare in comparison to others in Chile? Most recently in 2001-2014, street construction in Calama was the 28th-most disconnected out of the 33 cities in Chile. Its position in the ranks since 1975 has fallen; relative to other cities in Chile, street construction in Calama has become more connected. Calama ranked 23rd in 1975, 29th in 1976-1990, 30th in 1991-2000 and 28th in 2001-2014.

Calama and Antofagasta do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Calama fell steadily, while the SNDi of street constructions in Antofagasta peaked in 1976-1990.

To date, Calama is the 2nd-most disconnected out of the 2 cities in Antofagasta. Its position in the ranks since 1975 has fallen; relative to other cities in Antofagasta, the street network in Calama has become more connected. Calama ranked 1st in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

Calama and Chile do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Calama fell steadily, while the SNDi of street constructions in Chile rose steadily.

To date, Calama is the 31st-most disconnected out of the 33 cities in Chile. Its position in the ranks since 1975 has fallen; relative to other cities in Chile, the street network in Calama has become more connected. Calama ranked 23rd in 1975, 30th in 1976-1990, 31st in 1991-2000 and 31st in 2001-2014.

As of 2015, Calama had a built-up area of 10.67 square kilometers, and a population of 97444 people.

These are some other cities with approximately the same population: